A process for producing cumene by reacting benzene and propylene, a process for producing cumene hydroperoxide by oxidizing cumene, and a process for producing phenol and acetone by acid decomposing cumene hydroperoxide are each known. A process in which these reactions are combined is a production process for a phenol generally called as a cumene method, and is a main process for producing a phenol.
The cumene method has a property that acetone is produced simultaneously. Although the property becomes merits when acetone is simultaneously desired, when acetone is obtained in an excessive amount with respect to the demand thereof, the cost difference with propylene which is a raw material acts disadvantageously to lead to a bad economic efficiency. Therefore, in order to lead the cost difference between an olefin which is a raw material and a ketone which is co-produced to advantageousness, proposed is, for example, a process for simultaneously producing phenol and methylethyl ketone by oxidizing and acid decomposing secondary butyl benzene obtainable from n-butene and benzene (referred to Patent documents 1 and 2). In this process, since the selectivity of secondary butylbenzene hydroperoxide, which is an aimed product by oxidation of secondary butyl benzene, is only about 80% while acetophenone is incidentally produced in an amount of 15% or more, the yield of this process as a phenol production process does not reach to that of the cumene method.
Furthermore, a process for obtaining phenol and cyclohexanone by oxidizing and acid decomposing cyclohexylbenzene obtainable from cyclohexene and benzene is also proposed. In this process, since phenol is obtained by dehydrogenating resulting cyclohexanone, the by-production of a ketone can be avoided formally. In the oxidation reaction of cyclohexylbenzene, however, the yield of aimed cyclohexylbenzenehydroperoxide is low and the industrial value thereof is low.
Under the circumstances, for the cumene method having the highest yields of oxidation and acid decomposition, in order to avoid the defect of acetone incidentally produced with propylene which is a raw material while keeping the superiority, methods for reusing the acetone which is by-produced using various methods are proposed.
Acetone is easily convertible into isopropanol by hydrogenation. The process where this isopropanol is dehydrated to prepare propylene and then it is allowed to react with benzene to obtain cumene. Namely, a process of reusing acetone as a raw material for the cumene method is proposed (referred to Patent document 3). This process, however, has a problem of having two additional steps of hydrogenation step and dehydration step.
Consequently, processes of obtaining cumene by directly allowing isopropanol obtained by hydrogenation of acetone to react with benzene are proposed (referred to Patent documents 4 to 6). Particularly, the patent document 6 discloses a process of preparing isopropanol from acetone by-produced and producing phenol by using cumene obtained by allowing it to react with benzene. The process, however, also has an additional hydrogenation step as compared with the original cumene method.
On the other hand, as a process of reusing by-produced acetone without adding any steps to the conventional cumene method, namely a process of directly react acetone, benzene and hydrogen, a process of allowing them to react in the co-presence of hydrogen using a catalyst system which comprises a solid acid substance and a Cu compound is disclosed (Patent document 7). However, the process described in the patent document 7 has a tendency that propane is by-produced in the preparation of cumene.    Patent document 1: JP-A-S57-91972    Patent document 2: US-A-2004-0162448 specification    Patent document 3: JP-A-H2-174737    Patent document 4: JP-A-H2-231442    Patent document 5: JP-A-H11-35497    Patent document 6: JP-A-2003-523985    Patent document 7: JP-A-2005-513116